1. Technical Field of the Invention
The present invention relates in general to the field of communications networks, and in particular, by way of example but not limitation, to rehoming of radio base stations (RBSes) and to resource sharing in radio network controllers (RNCs) in wireless networks.
2. Description of Related Art
Access to wireless networks is becoming increasingly popular and important for business, social, and recreational purposes. Users of wireless networks now rely on them for both voice and data communications. Additionally, an ever increasing number of users demand both an increasing array of services and capabilities as well as larger and larger service coverage areas. To remedy the congestion caused by additional subscribers and to address demands for larger service coverage areas, network operators constantly strive to increase the size and capacity of their wireless networks. Expanding and improving the infrastructure necessary to provide additional capacity and a larger coverage area is an expensive and manpower-intensive undertaking.
One approach to adding capacity and expanding the coverage area of a wireless network (e.g., to ameliorate congestion resulting from an increasing subscriber base) is to increase the amount of wireless network infrastructure. The infrastructure of wireless networks is composed, in part, of RBSes and RNCs. The RBSes usually include one or more antennas or antenna arrays along with sufficient electronics (e.g., transceivers, control units, etc.) to service mobile stations (MSes) within their respective cell or cells, which typically number one or three per RBS. Each RNC usually controls and routes calls for multiple RBSes; RNCs also provide access to and through the wireless network for the RBSes. One approach to increasing wireless network infrastructure is to therefore add RBSes, and consequently one or more cells for the increasing subscriber base. However, adding RBSes to expand the network can cause RNCs to become overloaded, so one or more RNCs must be added. Once the decision has been made to invest in a new RNC, and the new RNC has been installed, loads frequently become unevenly distributed across the RNCs. As a result, one or more RNCs can become overloaded. RBSes thereafter need to be moved over, or xe2x80x9crehomedxe2x80x9d, from an old RNC to a new RNC. Conventional rehoming is an intensive, tedious, and time-consuming task that requires reconfiguration of both the radio and the transport networks. The RNCs require a particularly significant amount of reconfiguring, which heavily impacts traffic on connected RBSes.
In existing cellular systems, here exemplified by a system operating in accordance with the Global System for Mobile Communications (GSM) standard, in which Base Station Controllers (BSCs) correspond to RNCs, rehoming procedures require the following operations: (1) verify the hardware configuration in a target BSC by comparing it to the hardware configuration of a source BSC; (2) check if the relevant software version(s) for RBSes are available in the target BSC by comparing them with the registered version(s) in the source BSC; (3) copy the cell data from the source BSC to the target BSC; (4) copy the site data from the source BSC to the target BSC; (5) copy the neighbor cell data from the source BSC to the target BSC; (6) create new external cells data in the source BSC with state xe2x80x9cnot operatingxe2x80x9d; (7) create new external cells data in the target BSC with state xe2x80x9cnot operatingxe2x80x9d; (8) halt source cell in the source BSC; (9) block transceiver (TRX) resources in the RBS; (10) set old external cells data in the source and target BSC to state xe2x80x9cnot operatingxe2x80x9d.
With the above xe2x80x9cpreliminaryxe2x80x9d measures completed, (11) the operator next requests for the switching connection for the RBS to be moved from the source BSC to the target BSC. The rehoming procedure continues with the following operations: (12) update the Cell Global Identifier (CGI) in the Mobile Services Switching Center (MSC); (13) set new external cells data in the source and target BSCs with state xe2x80x9coperatingxe2x80x9d; (14) de-block TRX resources in the RBS; (15) activate target cell in the target BSC; (16) remove the cell data in the source BSC; (17) remove the site data in the source BSC; (18) remove N-cell data in the source BSC; (19) remove old external cells data in the source BSC; and (20) remove old external cells data in the target BSC.
These twenty (20) operations are performed manually in today""s systems. These operations could be automated by a work task support. With the work task support, the operator is guided through the operations and receives support by the system for performing each operation. The work task support will thus ease the burden currently placed on operators by rehoming procedures. Unfortunately, the work task support still suffers from a number of deficiencies. First, rehoming for third generation systems will still impact traffic (e.g., resources have to be blocked). Second, it will require interaction and time from the operator, and it will still permit the operator to introduce human errors. Third, the work task support cannot be used for load sharing. And fourth, the work task support will be complicated.
The deficiencies of the prior art are overcome by the method, system, and apparatus of the present invention. For example, it would be beneficial if RBSes could be rehomed to a different RNC automatically by the network without operator intervention. Furthermore, as heretofore unrecognized, it would be beneficial if the rehoming could be accomplished without blocking resources by a technique and mechanism that also enables load sharing between RNCs.
In certain embodiments, the present invention enables automatic RBS rehoming from a first RNC to a second RNC when the first RNC becomes overloaded and/or automatic resource sharing between/among RNCs when one RNC becomes overloaded. A managing/controlling entity receives load measuring reports from RNCs and analyzes them. If a first RNC is frequently and/or constantly experiencing an overcapacity condition, then an RBS of the RNC may be rehomed to a second RNC without operator intervention. If a first RNC temporarily experiences an overcapacity condition, then the workload of the first RNC may be shared by a second RNC also without operator intervention.
In other embodiment(s), the managing/controlling entity may determine whether there is an RNC experiencing an overcapacity condition by comparing capacity data included in the load measuring reports to a first predetermined threshold. The capacity data may be at least proportional to the number of connection establishments plus the number of connection releases per unit of time. The managing/controlling entity may determine whether there is an RNC that is a potential target RNC for rehoming an RBS to or for sharing loads with by ascertaining an RBS with link connections to multiple RNCs and determining whether one of the multiple RNCs has excess available capacity. The excess available capacity determination may be based on a comparison between capacity data included in the load measuring reports and a second predetermined threshold.
In still other embodiment(s), automatic RBS rehoming from a first RNC to a second RNC is effectuated by providing (e.g., optionally substantially instantaneous) take over from a resource point of view and a gradual take over of MS connections. For example, after determining that rehoming is to occur, the first RNC sends resource control data for the RBS resources to the second RNC. Thereafter, while ongoing connections are completed by the first RNC, new connections are established by the second RNC.
In still yet other embodiment (s) automatic resource sharing between a first and a second RNC for connections from an RBS that ordinarily are handled by the first RNC is effectuated based on relative levels of capacity and the aforementioned second predetermined threshold. For example, after determining that resource sharing is to occur, ongoing connections are completed through the first RNC, but new connections are typically established through the second RNC. Alternatively, if load balancing so dictates (e.g., the second RNC only has a small portion of excess available capacity and ongoing calls are being disconnected relatively quickly in the RBS), only a portion of the new connections may be established through the second RNC. These and other embodiments and aspects of the present invention are further explained hereinbelow.
The technical advantages of the present invention include, but are not limited to, the following. It should be understood that particular embodiments may not involve any, much less all, of the following exemplary technical advantages.
An important technical advantage of the present invention is that it enables automatic RBS rehoming without involving operators.
Another important technical advantage of the present invention is that it provides the ability to share resources between/among RNCs.
Yet another important technical advantage of the present invention is the ability to improve RBS rehoming inasmuch as operators do not have the ability to introduce errors.
Yet another important technical advantage of the present invention is the ability to optimally rehome RBSes without the need for work task support.
Yet still another important technical advantage of the present invention is that it does not impact in-service performance (ISP).
The above-described and other features of the present invention are explained in detail hereinafter with reference to the illustrative examples shown in the accompanying drawings. Those skilled in the art will appreciate that the described embodiments are provided for purposes of illustration and understanding and that numerous equivalent embodiments are contemplated herein.